1. Field
The present disclosure relates generally to wireless communication, and more specifically to local and remote Internet Protocol (IP) access via a femto access point or node.
2. Background
In order to extend the coverage area of macro base stations or to provide less expensive wireless communication services, a class of small base stations has been deployed. These access point (AP) base stations can be referred to as femto APs, femto nodes, Home Node B (HNB) units, Home evolved Node B (HeNB) units, femto Base Station (fBS), base station, Base Station Transceiver System (BSTS), etc., which are hereinafter referred to collectively or individually as “femto nodes”. Often these femto nodes utilize a low power, unlicensed bandwidth for installing in a private residence or place of employment to provide indoor wireless communication service. Typically, the femto node is connected to the Internet and the mobile operator's network via a Digital Subscriber Line (DSL), cable Internet access, T1/T3, or the like, and offers typical base station functionality, such as Base Transceiver Station (BTS) technology, radio network controller, and gateway support node services. This allows an Access Terminal (AT), also referred to as a terminal, a cellular/mobile device, a handset, or User Equipment (UE), to connect to wireless services via the femto node as an alternative to using a wireless wide area or cellular network service provided by the macro base station.
Additionally, a terminal may utilize services of a Wireless Local Access Network (WLAN), such as but not limited to a WLAN compliant with IEEE 802.11 standards. For example, a wireless mobile device can be used in what are commonly referred to as “Wi-Fi hotspots” to access Internet services. Often, local hosts within a coverage area of a WLAN can provide local Internet Protocol (IP) services, such as providing access to a desktop personal computer, printer, media server, file server, etc.
In some aspects, a femto node can provide a service to a terminal called Local IP Access (LIPA). LIPA allows the terminal to communicate, using cellular air-interfaces (such as cdma2000, UMTS, or LTE), with a local area network in which the femto node resides. Another complimentary service that a femto node may also enable is Remote IP Access (RIPA). RIPA allows a terminal to have IP connectivity with a local area network in which the femto node resides even when the terminal is not connected over-the-air with the femto node. These two services allow a user to access a home local access network from anywhere using a cellular terminal.
In a typical local area network, one-to-many Internet Protocol (IP) packets are used when a host wants to discover a service, such as a media server or a printer, provided by another host on the same LAN. Similarly, one-to-many IP packets are also used by a host that wants to advertise a service that it can provide in the LAN. Both Ethernet and WiFi (802.11) have built-in mechanisms that deal with one-to-many IP packets effectively. In the current cellular air-interface protocols, however, one-to-many IP packets are rarely used.
Conventionally, using cellular air-interface protocols, one-to-many IP packets associated with a terminal receiving LIPA or RIPA services through a femto node have a number of detrimental effects on the terminal. For example, standby time of a battery powering the terminal is significantly reduced because of the one-to-many IP packets. Furthermore, the channel elements on the femto node are inefficiently utilized, thus reducing the number of terminals that the femto node can support.
For example, in order for a femto node to deliver a broadcast or multicast (i.e., one-to-many) IP packet associated with a LAN for LIPA or RIPA service, each terminal that connects with the femto node (either locally or remotely) needs to be paged, initiate a connection request, receive the packet and then maintain the traffic channel until a dormancy timer expires. Since the one-to-many IP packet associated with the LAN is typically very small (a few hundred bytes at most), the packet would be delivered in a few hundred milliseconds at the beginning of the connection for typical 3G/4G throughput. However, unlike WiFi, where the terminal receives a multicast packet and then goes back to sleep immediately, a cellular terminal will stay connected after the packet is delivered until the dormancy timer expires where the typical dormancy timer is set to 2-10 seconds.
To make the matter worse, the number of one-to-many IP packets in a LAN typically scale with the number of hosts that are connected in the LAN, e.g., in an Enterprise LAN with tens of Windows PCs, a one-to-many IP packet can be observed every second. With this frequency of one-to-many (broadcast/multicast) packets, the terminal may almost never drop the connection. This scenario leads to significant reduction in the standby time of the terminal, even without further user interaction with the terminal.
Thus, improvements in LIPA and RIPA service provided by a femto node to a terminal are desired in view of the current problems of poor standby time and lengthy maintaining of the traffic channel connection, which yields poor multiplexing gain on the limited channel elements of the femto node.